Inspired by an ancient myth, Darklight stars Shiri Appleby as the immortal Lilith, long hunted by a secret society known as the Faith. Her true nature concealed by a powerful spell, Lilith lives as a 24-year-old woman with no memory of her ageless past. Now, the Faith's chief agent, William Shaw, must recruit Lilith and train her to use her mystical power, known as Darklight, for the good of humanity. So begins Lilith's heroic journey; to slay a deadly demon and come to terms with her own dark past.

The crew of the first manned mission to Mars crash land on the surface in search of a clean everlasting power source they believe to be hidden somewhere beneath the ground. However, the crew find themselves in the middle of a civil war between the High Priest of Mars' royal guards and the High Priestess' warriors. The crew is divided with one half deciding to help the High Priest make peace with Earth and the other side with the High Priestess who is secretly plotting to kill her husband and invade Earth.